Gremlins

When Gremlins hit theatres in 1984 some genius gave it a PG rating, which meant it was classed as family viewing. Children as young as four could watch it if they were with their parents.

If they did, they were likely scarred for life because the titular characters were a bunch of blood-thirsty malevolent killers who used knives, crockery and anything else they could get their claws on to attack people. At one point they eat a guy dressed up as Santa Claus alive. Really.